Multi-suture knotless anchor for attaching tissue to bone and related method

ABSTRACT

A multi-suture knotless anchor and related method for securing soft tissue, such as tendons, to bone are described. The suture anchor includes a body, a sleeve, and an outer deformable bone locking structure. The bone locking structure has a first low profile configuration for insertion into the bone, and a second larger profile configuration for engaging the bone when actuated. The bone anchor and methods permit a suture attachment that lies beneath the cortical bone surface and does not require tying of knots in the suture.

BACKGROUND OF THE INVENTION

This invention relates generally to methods and apparatus for attachingsoft tissue to bone, and more particularly to anchors and methods forsecuring connective tissue, such as ligaments or tendons, to bone. Theinvention has particular application to arthroscopic surgical techniquesfor reattaching soft tissue in a minimally invasive procedure.

Less invasive arthroscopic techniques are continuing to be developed inan effort to address the shortcomings of open surgical repair. Workingthrough small trocar portals allow surgeons to cause less trauma than anopen procedure. However, less invasive techniques present uniquechallenges as the surgeon has less space to manipulate tools andimplants.

Unfortunately, the skill level required to facilitate entirelyarthroscopic repair tissue is inordinately high. Intracorporeal suturingis clumsy and time consuming, and only the simplest stitch patterns canbe utilized. Extracorporeal knot tying is somewhat less difficult, butthe tightness of the knots is difficult to judge, and the tension cannotlater be adjusted. Also, because of the use of bone anchors to provide asuture fixation point in the bone, the knots that secure the softtissues to the anchor by necessity leave the knot bundle on top of thesoft tissues. In the case of certain procedures the knot bundle left inthe tissue can be felt by the patient postoperatively when the patientexercises the joint. Often the knots tied arthroscopically are difficultto achieve, impossible to adjust, and are located in less than optimalareas of the shoulder. Suture tension is also impossible to measure andadjust once the knot has been fixed.

Another significant difficulty with current arthroscopic repairtechniques is shortcomings related to currently available sutureanchors. Suture eyelets in bone anchors available today, which like theeye of a needle are threaded with the thread or suture, are small inradius, and can cause the suture to fail at the eyelet when the anchoris placed under high tensile loads.

There are various bone anchor designs available for use by an orthopedicsurgeon for attachment of soft tissues to bone. The basic commonalitybetween the designs is that they create an attachment point in the bonefor a suture that may then be passed through the soft tissues and tied,thereby immobilizing the soft tissue. This attachment point may beaccomplished by different means. Screws are known for creating suchattachments, but suffer from a number of disadvantages, including theirtendency to loosen over time, requiring a second procedure to laterremove them, and their requirement for a relatively flat attachmentgeometry.

Another approach is to utilize the difference in density in the corticalbone (the tough, dense outer layer of bone) and the cancellous bone (theless dense, and somewhat vascular interior of the bone). The corticalbone presents a kind of hard shell over the less dense cancellous bone.The aspect ratio of the anchor is such that it typically has a longeraxis and a shorter axis and usually is pre-threaded with a suture. Thesedesigns use a hole in the cortical bone through which an anchor isinserted. The hole is drilled such that the shorter axis of the anchorwill fit through the diameter of the hole, with the longer axis of theanchor being parallel to the axis of the drilled hole. After deploymentin to the cancellous bone, the anchor is rotated 90 degrees so that thelong axis is aligned perpendicularly to the axis of the hole. The sutureis pulled, and the anchor is seated up against the inside surface of thecortical layer of bone. Due to the mismatch in the dimensions of thelong axis of the anchor and the hole diameter, the anchor cannot beretracted proximally from the hole, thus providing resistance topull-out. These anchors still suffer from the aforementioned problem ofeyelet design that stresses the sutures.

Still other prior art approaches have attempted to use a “pop rivet”approach. This type of design requires a hole in the cortical bone intowhich a split shaft is inserted. The split shaft is hollow, and has atapered plug leading into its inner lumen. The tapered plug is extendedout through the top of the shaft, and when the plug is retracted intothe inner lumen, the tapered portion causes the split shaft to be flaredoutwardly, locking the device into the bone.

Other methods of securing soft tissue to bone are known in the priorart, but are not presently considered to be feasible for shoulder repairprocedures, because of physicians' reluctance to leave anything but asuture in the capsule area of the shoulder. The reason for this is thatstaples, tacks, and the like could possibly fall out and cause injuryduring movement. As a result of this constraint, the attachment pointoften must be located at a less than ideal position. Also, the tacks orstaples require a substantial hole in the soft tissue, and make itdifficult for the surgeon to precisely locate the soft tissue relativeto the bone.

As previously discussed, any of the anchor points for sutures mentionedabove require that a length of suture be passed through an eyeletfashioned in the anchor and then looped through the soft tissues andtied down to complete the securement. Much skill is required, however,to both place the sutures in the soft tissues, and to tie knots whileworking through a trocar under endoscopic visualization.

There have been attempts to solve some of the problems that exist incurrent anchor designs. One such approach is disclosed in U.S. Pat. No.5,324,308 issued to Pierce. In this patent, there is disclosed a sutureanchor that incorporates a proximal and distal wedge component havinginclined mating faces. The distal wedge component has two suture threadholes at its base through which a length of suture may be threaded. Theassembly may be placed in a drilled hole in the bone, and when tensionis placed on the suture, the distal wedge block is caused to ride upagainst the proximal wedge block, expanding the projected area withinthe drilled hole, and locking the anchor into the bone. This approach isa useful method for creating an anchor point for the suture, but doesnot in any way address the problem of tying knots in the suture to fixthe soft tissue to the bone.

The problem of placing sutures in soft tissues and tying knots in anendoscopic environment is well known, and there have been attempts toaddress the problem and to simplify the process of suture fixation. Onesuch approach is disclosed in U.S. Pat. No. 5,383,905 issued to Golds etal. The patent describes a device for securing a suture loop aboutbodily tissue that includes a bead member having a longitudinal bore andan anchor member adapted to be slidably inserted within the bore of thebead member. The anchor member includes at least two axial compressiblesections which define a passageway to receive two end portions of asuture loop. The axial sections collapse radially inwardly uponinsertion of the anchor member within the bore of the bead member tosecurely wedge the suture end portions received within the passageway.

Although the Golds et al. patent approach utilizes a wedge-shaped memberto lock the sutures in place, the suture legs are passing through thebore of the bead only one time, in a proximal to distal direction, andare locked by the collapsing of the wedge, which creates an interferenceon the longitudinal bore of the anchor member. Also, no provision ismade in this design for attachment of sutures to bone. The design isprimarily suited for locking a suture loop, such as is used for ligationor approximation of soft tissues.

An approach that includes bone attachment is described in U.S. Pat. No.5,584,835 issued to Greenfield. In this patent, a two part device forattaching soft tissue to bone is shown. A bone anchor portion is screwedinto a hole in the bone, and is disposed to accept a plug that has beenadapted to receive sutures. In one embodiment, the suture plug isconfigured so that when it is forced into its receptacle in the boneanchor portion, sutures that have been passed through an eyelet in theplug are trapped by friction between the wall of the anchor portion andthe body of the plug portion.

Although there is some merit to this approach for eliminating the needfor knots in the attachment of sutures to bone, a problem with beingable to properly set the tension in the sutures exists. The user isrequired to pull on the sutures until appropriate tension is achieved,and then to set the plug portion into the bone anchor portion. Thisaction increases the tension in the sutures, and may garrote the softtissues or increase the tension in the sutures beyond the tensilestrength of the material, breaking the sutures. In addition, the minimalsurface area provided by this anchor design for pinching or locking thesutures in place will abrade or damage the suture such that the suture'sability to resist load will be compromised.

A disclosure that incorporates bone attachment and eliminates knot tyingis set forth in U.S. Pat. No. 5,702,397 issued to Goble et al. Oneembodiment, in particular, is shown in FIG. 23 of that patent andincludes a bone anchor that has a threaded body with an inner cavity.The cavity is open to one end of the threaded body, and joins two lumensthat run out to the other end of the threaded body. Within the cavity isdisposed a gear, journaled on an axle. A length of suture is threadedthrough one lumen, around the gear, and out through the other lumen. Aball is disposed within the cavity to ride against a tapered race andlock the suture in place. What is not clear from the patent disclosureis how the force D shown as the tension in the suture would lock theball into the race. Although this embodiment purports to be aself-locking anchor adapted for use in blind holes for fixing suturesinto bone, the construct shown is complicated, and does not appear to beadequate to reliably fixate the suture.

PCT Publication WO 01/10312 by McDevitt et al. also describes aself-locking suture anchor for attaching soft tissue to bone. In thisdevice a tissue anchor holds a filament within the anchor so that anapplied force greater than a threshold force causes the filament to movelongitudinally, while an applied force that is less than the thresholdforce does not move the filament.

U.S. Patent Publication No. 2008/0051836 by Foerster et al. describesknotless bone anchor body having an outer rigid anchoring structure andan interior lumen. The lumen is sized to receive a locking plug and tocompress and lock a suture situated therein.

A number of the suture anchors described above have static or fixedbarbed anchor designs. Namely, the outer diameter of the anchoringstructure is fixed (or constant) irrespective of the bone quality. Thisis a disadvantage when the bone is relatively soft. The anchor may havea tendency to pull out.

Despite the above, a new approach is desired for repairing or fixingsoft tissues to bone. In particular a new approach is desired thatembeds a suture anchor below the cortical bone surface, utilizesmultiple sutures, and is knotless.

SUMMARY OF THE INVENTION

A suture anchor for securing a soft tissue to a bone with at least onesuture comprises a first undeployed configuration in which tissue may bedrawn towards the suture anchor by applying tension to a free limb ofthe suture, and a second deployed configuration in which the sutureanchor is fixed in the bone and the suture is locked in the sutureanchor thereby securing the tissue to the bone. The suture anchorincludes: an anchor body having a proximal section, an elongateintermediate section, and a distal section; a bone locking member atleast partially disposed about the elongate intermediate section andforming a cavity between an inner surface of the bone locking member andan outer surface of the elongate intermediate section. The suture anchoralso includes a sleeve member which moveably cooperates with the anchorbody and the bone locking member to slide into the cavity along theelongate intermediate section thereby expanding the bone locking memberand compressing the at least one suture between the outer surface of theelongate intermediate section and an inner surface of the sleeve member.The shape of the cavity may vary. In one embodiment the cavity has anannular shape.

In another embodiment, the bone locking member comprises a plurality ofdeflecting sections which deflect outwardly from the anchor body whenthe sleeve member is urged into the cavity. The plurality of deflectingsections may comprise wings. In one embodiment, the plurality of wingscomprise at least three discrete wings.

In another embodiment, the suture anchor comprises a bone piercing tip.The bone piercing tip may taper from a proximal base to a distal end.The base may have an outer diameter of at least 4 mm.

In another embodiment the suture anchor body comprises a suture guidewhich guides the suture from one side of the anchor body to the otherside of the anchor body. The suture guide may be an aperture extendingthrough the distal section of the anchor body.

In another embodiment, the suture anchor comprises ridges which engagethe bone to hold the anchor in the bone. The ridges may be situated onthe bone locking member and/or the sleeve. Additionally, the distalsection of the anchor body may comprise ridges.

The suture anchor may be formed of various materials. In one embodiment,the suture anchor is formed of a biocompatible polymer.

In another embodiment a knotless suture anchoring system for anchoring alength of suture with respect to a bone comprises: an anchor insertioninstrument comprising a handle, and an elongate rigid shaft extendingdistally from the handle; an anchor body detachably connected to theinstrument elongate rigid shaft. The anchor body comprising a suturecarrying portion allowing the suture to pass from a first side of theanchor body to an opposite side of the anchor body. The anchoring systemfurther comprising a bone locking member disposed on the anchor body. Inembodiments, the bone locking member comprises a bone anchoringstructure extending from a base and radially spaced from theintermediate section of the anchor body such that a cavity is definedbetween an outer surface of the anchor body and the inner surface of thebone anchoring structure. The cavity is sufficient in size to allow thelength of suture to be drawn through the cavity and to the suturecarrying portion. The anchoring system also includes a sleeve memberslidably disposed on the shaft distal end section of the instrument andproximal to the anchor body. The sleeve member has an outer diametersufficient in size and shape to radially expand the anchoring structurewhen pushed along the shaft distal end section and into the cavity, andthe sleeve member having an inner diameter sufficient in size and shapeto compress a length of suture between the anchor body and an innersurface of the sleeve.

In another embodiment the system comprises a snare extending through atleast a portion of the insertion instrument and the suture carryingportion of the anchor bone such that when a distal portion of the snareis affixed to the suture, withdrawal of the snare pulls the suturethrough the suture carrying portion of the anchor body and the distalportion of the insertion instrument.

In another embodiment, the distal end section of the anchor comprises apointed tip.

In another embodiment, the system includes a section of tensile weaknessor engineered notch along the instrument shaft permitting the shaft tobe detached from the anchor body proximal end upon application of apredetermined tensile force on the shaft in the proximal direction.

In another embodiment a method for knotless securing of soft tissue tobone comprises stitching tissue with at least one suture; loading ananchor assembly with the at least one suture, the anchor assembly beingdetachably connected to the end of an insertion instrument; manipulatingthe anchor assembly into the bone; tensioning a free end of the sutureto approximate the tissue to the anchor assembly; moving a sleeve memberinto the anchor assembly to deploy a bone locking structure of theanchor assembly and to compress the suture; and retracting the insertioninstrument leaving the anchor assembly embedded in the bone, and thetissue secured to the bone.

In another embodiment loading the anchor assembly with the at least onesuture comprises loading the anchor assembly with a plurality ofsutures.

In another embodiment loading the anchor assembly is performed bysnaring the sutures. Snaring may be performed by inserting the lengthsof the sutures in a wire loop of a snare device detachably affixed tothe distal section of the shaft, and pulling on a snare grip to draw thesutures through the anchor assembly and the instrument.

In another embodiment manipulating the anchor and suture into a bonecomprises hammering the proximal end of the insertion instrument. Also,in embodiments, the tensioning is performed prior to the manipulatingstep. The tensioning may be performed semi-automatically

In another embodiment the tissue is a rotator cuff tendon and the boneis the humeral head.

In another embodiment the moving step includes compressing a firstsection of suture between the anchor body and the sleeve member and asecond section of the suture between a bone surface and an exterior ofthe bone locking structure. The moving step may include pushing thesleeve into the cavity until a stop on the anchor body prevents furthermovement.

In another embodiment, the method comprises toggling the anchor assemblyto a tilt angle. The toggling may be performed by applying tension onthe tissue side of the suture.

The invention, together with additional features and advantages thereof,may best be understood by reference to the following description takenin conjunction with the accompanying illustrative drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of a suture anchor in an undeployedconfiguration;

FIG. 1B is a perspective view of the suture anchor shown in FIG. 1A in adeployed configuration;

FIGS. 2A and 2B are sectional views of the suture anchor and insertioninstrument shown in FIGS. 1A and 1B respectively;

FIG. 3A is a proximal end view of a body component of a suture anchor;

FIG. 3B is a sectional view of the body component taken along line 3B-3Bof FIG. 3A;

FIG. 4A is a side view of a sleeve component of a suture anchor;

FIG. 4B is a sectional view of the sleeve component taken along line4B-4B of FIG. 4A;

FIGS. 4C and 4D are proximal and distal end views respectively of thesleeve component shown in FIG. 4A;

FIG. 5A is a perspective view of a bone locking component of a sutureanchor;

FIG. 5B is a side view of the bone locking component shown in FIG. 5A;

FIG. 5C is a sectional view of the bone locking component taken alongline 5C-5C of FIG. 5B;

FIG. 5D is a proximal end view of the bone locking component of FIG. 5B;

FIG. 6 is an illustration of a suture anchor system including a sutureanchor and multiple sutures connected thereto;

FIGS. 7 and 8 are partial cross sectional views of a suture anchorinserted in a bone in and undeployed and deployed configurationrespectively;

FIG. 9 is a partial cross sectional view of a suture anchor inserted ina bone in a deployed configuration and with the insertion instrumentwithdrawn;

FIGS. 10A-10D are various views of another plug component of a sutureanchor assembly;

FIGS. 11A-11C are perspective views of another suture anchortransitioning from a first undeployed configuration, to an intermediateconfiguration, and to a deployed or locked configuration respectively;

FIG. 12 is a flowchart of the steps to deploy a suture anchor; and

FIGS. 13A and 13B are illustrations of a suture anchor in bone in analigned position and an offset position respectively.

DETAILED DESCRIPTION

Before the present invention is described in detail, it is to beunderstood that this invention is not limited to particular variationsset forth herein as various changes or modifications may be made to theinvention described and equivalents may be substituted without departingfrom the spirit and scope of the invention. As will be apparent to thoseof skill in the art upon reading this disclosure, each of the individualembodiments described and illustrated herein has discrete components andfeatures which may be readily separated from or combined with thefeatures of any of the other several embodiments without departing fromthe scope or spirit of the present invention. In addition, manymodifications may be made to adapt a particular situation, material,composition of matter, process, process act(s) or step(s) to theobjective(s), spirit or scope of the present invention. All suchmodifications are intended to be within the scope of the claims madeherein.

Methods recited herein may be carried out in any order of the recitedevents which is logically possible, as well as the recited order ofevents. Furthermore, where a range of values is provided, it isunderstood that every intervening value, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range is encompassed within the invention. Also, it iscontemplated that any optional feature of the inventive variationsdescribed may be set forth and claimed independently, or in combinationwith any one or more of the features described herein.

All existing subject matter mentioned herein (e.g., publications,patents, patent applications and hardware) is incorporated by referenceherein in its entirety except insofar as the subject matter may conflictwith that of the present invention (in which case what is present hereinshall prevail).

Reference to a singular item, includes the possibility that there areplural of the same items present. More specifically, as used herein andin the appended claims, the singular forms “a,” “an,” “said” and “the”include plural referents unless the context clearly dictates otherwise.It is further noted that the claims may be drafted to exclude anyoptional element. As such, this statement is intended to serve asantecedent basis for use of such exclusive terminology as “solely,”“only” and the like in connection with the recitation of claim elements,or use of a “negative” limitation. It is also to be appreciated thatunless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs.

The present invention provides improved methods and devices for knotlesssuturing of tissue. Although the variation discussed herein discussesuse of a suture, the term “suture” may include any piece of materialthat is used to close a wound or connect tissue (e.g., catgut, thread,wire, etc.) so long as the material can be used with the other portionsof the anchor as described herein. Accordingly, sutures as describedherein may include polymeric, metallic, or other types of sutures.

For illustrative purposes, the examples discussed herein show the use ofthe anchoring system to suture soft tissue to a bone structure, namely,the humeral head. The present invention is particularly well-suited forrepairing rotator cuff injuries by re-attaching the rotator cuff tendonto the outside of the humeral head. Embodiments of the present inventionpermit minimally invasive surgeries on such injuries and greatlyfacilitate rapid and secure fixation of the rotator cuff tendon to thehumeral head. However, it should be understood that the same principlesdescribed herein apply to the repair of other injuries in which softtissue is to be re-attached to a bone structure or other tissue region.For example, in embodiments, the soft labrum may be attached to theglenoid. In other embodiments, other soft or connective tissues areattached to bone bodies or other tissues as the case may be.

Anchor Structure Overview

FIGS. 1A and 1B show an anchor assembly 10 for securing soft tissue to abone with one or more sutures in an undeployed and deployedconfiguration respectively. FIGS. 2A and 2B show cross sectional viewsof the anchor shown in FIGS. 1A and 1B respectively. The anchor assembly10 is shown comprising a plurality of components (namely, sleeve 12,wings 14, and body 16). The anchor components movably cooperate togetherto provide two configurations including: (a) a first undeployedconfiguration in which the tissue may be drawn towards the anchor byapplying tension to the free ends or limbs of the suture; and (b) asecond deployed configuration in which the anchor is fixed in the bone,and the suture is locked in the anchor thereby securing the tissue tothe bone.

FIGS. 1A and 2A show the anchor assembly 10 in an undeployedconfiguration. In particular, sleeve member 12 is shown positionedproximal to wings 14, and anchor body 16. Wings 14 are undeformed,substantially parallel to the body 16, and unexpanded. In thisundeployed state, it can be seen that the sutures are free to slide andmove through the anchor upon applying a tension to either the tissueside 20 or the free side 22 of the sutures. In particular, the suturefree legs 22 may be pulled so as to pull soft tissue attached to thebound legs 20 closer to the suture anchor.

Suture guide 50 may have an eyelet, groove, or slit shape. Preferablyguide has a smooth surface to allow for easy suture sliding during use.Additionally, inner body 16 may have an elongate nest or groove (notshown) to provide some limitation to any lateral motion of the suture(i.e. to keep the suture from slipping off the shaft). The suture itselfmay also comprise a low friction material such as polyester suture tocreate an overall low friction environment. Examples of sutures includewithout limitation low friction UHMWPE suture and polyester suture.

At least one suture which includes at least one bound leg 20 is shownthreaded through the eyelet 50 and redirected proximally back throughthe lumen 51 of the instrument 30 to result in free legs 22. The boundside or leg 20 is considered bound because in practice, this leg or limbof the suture is “bound” to the soft or connective tissues to beattached to the target tissue such as bone by virtue of passing thesutures through the connective or soft tissues using conventionalsuturing techniques known in the art. The free side or leg 22 isconsidered “free” because the surgeon or practitioner, in practice, hascontrol over this limb or leg of the suture with his or her hands orappropriate instrumentation.

FIGS. 1B and 2B show the anchor assembly 10 in a deployed configuration.In particular, the sleeve 12 has been urged distally (e.g., pushed) byan instrument driver surface (not shown) onto the anchor body 16. As thesleeve is urged distally onto the anchor body 16, the outer surface ofthe sleeve 12 displaces wings 14, and in particular, radially expandsthe wings to embed, affix, or lock the anchor assembly in a bone.

The sleeve 12 also serves to lock or retain the suture. As the sleeve 12is urged distally onto the anchor body 16, the inner surface of thesleeve compresses the suture against the outer surface of anchor body(or plug portion) 16 of the anchor assembly.

The embodiment shown in FIG. 2B also includes a second locking surface54 which is off-axis, namely, not parallel to the longitudinal axis ofthe suture anchor body 16. The combination of contact surfaces tocompress the suture aid to lock the suture and prevent slip. Thecombination of contact surfaces at angles to one another creates atortuous path, increasing frictional forces on the suture when theanchor assembly is in the deployed configuration.

Additionally, in embodiments, the anchor assembly does not compress ordeform the anchor body 16, nor the sleeve 12, and a gap (G) is presentbetween the outer diameter of the anchor body 16 and the inner diameterof the sleeve 12. This gap allows for multiple sutures to be snared orthreaded through the anchor assembly and attached to tissue. This gapensures each of the suture lock and the bone lock function independentlyand effectively regardless of the number of sutures. This is anadvantage of the present invention.

Anchor Body

FIGS. 3A and 3B show an anchor body or plug component 16 with the othercomponents of the anchor assembly removed for clarity. The anchor body16 is shown having a proximal section 42, an elongate intermediatesection 44, and a tissue penetrating distal end section 46. An exemplaryoverall length (L1) of the plug component ranges from 0.55 to 0.75 inchand more preferably about 0.63 inch.

The distal end section 46 preferably is adapted to pierce bone. Thepiercing tip may facilitate the anchor to be pounded or driven into bonewith a mallet or hammer-like instrument. The shape of the tip may varywidely. It may be solid, and comprise a sharp point. A dart shape isshown in FIG. 3B. The tip increases in diameter from the distal point atan angle (α) from the centerline ranging from about 20 to 27 degrees andpreferably about 23 degrees. The distal tip 46 increases in diameterfrom the distal to the proximal end until a maximum diameter is reached(D1) at the proximal end of the end section 46. Preferably, D1 rangesfrom 0.15 to 0.25 inch and more preferably from about 0.18 inch.However, the invention is intended only to be limited as recited in theappended claims.

The distal end section 46 also shows a suture holder or guide 50 whichdirects one or more sutures from one side of the suture anchor to theother side as shown, e.g., in FIGS. 1-2. The suture guide 50 may be inthe form of an aperture or opening as shown. The aperture preferably hasa diameter in the range of 0.060 to 0.080 inch. Additionally, the sutureguide may comprise a groove or other shape which serves to guide thesutures into and out of the anchor assembly. The suture guide preferablyis smooth so as to not damage the sutures nor provide friction when thesuture is being loaded or the tissue approximated as will be discussedin more detail below.

The distal tip 46 may also comprise a coating or material to facilitatebone penetration. For example, the tip may be formed from a metal suchas 316L stainless steel, or titanium, or a polymer such as PEEK. Theanchor body including the tip may be formed of one material, or acombination of materials. In one embodiment, the anchor body is aninjection molded biocompatible polymer such as PEEK. In anotherembodiment it is machined. Alternative embodiments may include a bluntedtip for inserting into a prepared bone passage or a threaded or tissuecutting tip.

The intermediate elongate section 44 is adapted to slide within andrelative to the sleeve as shown in FIGS. 1 and 2. The elongate section44 fits (or plugs) the sleeve member. The size of the intermediatesection may vary. An exemplary diameter (D2) of the intermediate sectionranges from 0.090 to 0.102 inch and more preferably is about 0.100 inch.An exemplary length (L2) of the intermediate section is about 0.380 to0.420 inch and more preferably about 0.400 inch.

The intermediate section 44 is shown terminating at a stop surface 48.The stop 48 arises from the geometry of the piercing tip 46 describedabove, and also acts to limit distal movement of the wings 14, andsleeve relative to the body 16. Additionally, as described herein, thesuture lengths may be compressed against stop surface 48 increasingsuture locking and retention.

Proximal section 42 is shown comprising a sacrificial area and means toconnect to an insertion tool such as the insertion instrument 30 shownin FIGS. 1-2. In particular, the anchor body 16 shown in FIG. 3Bincludes a plurality of grooves 52 for receiving a threaded end of aninsertion tool. Distal to the threads 52 is a weakened section 55 havinga reduced diameter or thickness. As will be discussed further below,after the anchor is deployed and affixed in the bone, the insertion toolis retracted. The shaft shears or breaks away from the anchor assemblyat the sacrificial region 54. The sacrificial region is adapted to breakat a tension of about 80 to 100 pounds whereas the force required toslide the sleeve over the intermediate section of the anchor body is 15to 60 pounds. Thus, it is a sacrificial section that predictably breaks,leaving the anchor assembly properly embedded in the bone. It is also tobe understood, however, that a wide range of detaching means may beemployed to detach the insertion instrument from the anchor. Anon-limiting example of a detachment means is an internal threadedportion within the shaft. Upon application of sufficient stress betweenmating threaded portions, one or both of the threaded portions strip torelease the anchor from the system. Additional examples include, withoutlimitation, a frictional press-fit or barbed coupling may be employed.The amount of force required to separate the anchor from the deploymentsystem is sufficiently high to minimize inadvertent deployment but alsoto ensure that the surgeon can deploy the anchor as desired.

Sleeve

FIGS. 4A-4D show a sleeve component 12 of an anchor assembly. Sleeve 12is shown having a generally tubular shape and a lumen 62 extending froma proximal end 64 to a distal end 66 of the sleeve. The lumen is shownhaving a constant diameter (D3). An exemplary diameter (D3) for thesleeve 12 ranges from 0.105 to 0.120 inch and more preferably is about0.108 inch. An exemplary length (L3) of the sleeve ranges from 0.160 to0.350 inch and more preferably is about 0.250 inch.

As described herein, one of the functions of the sleeve is to lock thesuture. In particular, sleeve coaxially surrounds a portion of theintermediate section 44 of the anchor body 16, and compresses a suturedisposed therebetween.

Another function of the sleeve is to activate the bone lock or fix theanchor in the bone. The geometry of the sleeve enables bone locking. Inparticular, sleeve preferably has a tapered exterior. The outer diameterof the sleeve 12 increases in diameter from the distal end 66 to theproximal end 64. The diameter (D4) at the distal end may range from0.130 to 0.150 inch and the diameter (D5) at the proximal end may rangefrom 0.150 to 0.170 inch. The transition from the smaller diameter tolarger diameter may be smooth, linear, or have a radius (R1). Asdiscussed further below, urging sleeve into the bone affixationstructure causes the affixation structure (e.g., the deflecting wings)to engage the bone.

Deflectable Wing Members

FIGS. 5A-5D show a bone locking or affixing structure 14. The bonelocking component 14 is shown having three outwardly deflectable arms orwings 72. The arms extend from distal end section or base 75. The wingsare separated by slots 74. In an application, the wings 72 are deflectedto engage the bone and affix the anchor therein.

The bone locking structure 14 is shown having a generally tubular shapewith a slight inward taper. In embodiments, and when undeployed, theouter diameter (D7) of the proximal end may range from 0.150 to 0.250inch. In embodiments, the outer diameter (D8) of the distal end mayrange from 0.150 to 0.200 inch. Unlike the proximal end, the outerdiameter of the distal end remains relatively constant and does notexpand. In embodiments, the wall thickness (T) may range from 0.010 to0.040 inch. Additionally, an exemplary overall length (L5) for the bonelocking structure ranges from 0.160 to 0.400 inch and more preferably isabout 0.330 inch. An exemplary length (L4) of the wings ranges from0.100 to 0.350 inch and more preferably is about 0.270 inch.

In embodiments, the wings 72 collectively define an inner cavity 73. Thedeformable cavity 73 is sized and shaped to receive inner sleeve 12. Assleeve 12 is pushed into the cavity 73, the wing members 72 are forcedto deflect and expand outwardly. The wing members 72 deploy and gripinto the bone.

The amount of deflection may be characterized by, amongst other things,the difference in outer diameter (D7) of the bone locking structurebetween states, namely, the undeployed first state versus the deployedsecond state. An exemplary outer diameter (D7) of the proximal end whenundeployed ranges from 0.160 to 0.180 inch and more preferably is about0.160 inch. When deployed, the outer diameter D7 may expand to 0.240 to0.260 inch or more. Consequently, the percent expansion in Area (A)ranges from 100 to 165%.

Additionally, as mentioned above, the degree or expansion is affected bybone quality. The wings tend to expand to a greater degree in softerbone. This is an advantage over static or fixed barbed anchor designs inwhich the diameter of the anchoring structure is fixed/constantirrespective of the bone quality.

The bone anchor structure is also shown having a base and distalaperture 75. Distal aperture 75 is sized to cooperate with the plugcomponent 16. In particular, distal aperture 75 has a size and shape toreceive the intermediate section 44 of the plug member 16. The distalaperture 75 is held fixed and against stop surface 48 of the plugcomponent 16 so that further axial movement of the wings is prohibitedas the sleeve is urged into cavity 73.

The distal end opening 75 remains constant. An exemplary distal endinner diameter (D9) ranges from 0.110 to 0.120 inch.

The bone locking component 14 may also comprise one or more openings orwindows 76 to aid in providing space or room for the sutures. Forexample, window 76 is sized to carry or guide multiple sutures along theanchor body towards the distal end.

Barbs or ridges 80 are shown on the deflecting members 72. The ridgesserve to grip the bone tissue. The change in height (or step) of thebarbs or ridges ranges from 0.030 to 0.050 inch.

The illustration of the ridges is intended for example only. The sutureanchor of the present invention may incorporate a number of features orstructures to achieve a bone lock including, for example, assuming alarger profile using a variety of anchoring means such as expansionribs, moly-bolts, rivets, wings, and other mechanisms. Variations arewithin the scope of the device and methods described herein.Additionally, variations include anchoring structures that do not fullyencircle the anchor body, namely, partial or discontinuous ridges, ribs,and other structures. Also, the above mentioned size ranges and shapesare intended as exemplary only and the invention is not intended to beso limited except as recited in the appended claims.

Anchor Implantation Using Instrument

FIGS. 6-9 illustrate a suture anchor being implanted. As shown, sutures28,29 may be previously stitched, connected to or looped through tissue150 and loaded within anchor 132 (e.g., routed through the anchor usinga snare) and instrument 128. Instrument 128 may also have lateralaperture or opening 140, located at the distal portion of the instrumentbut proximal to anchor wings 164, operable to allow passage of sutures28, 29 from the instrument to the anchor. Sutures 28,29 may extenddistally from aperture 140 within anchor 132, through eyelet, to thetissue 150, and return proximally along the same path and may beconnected with a portion of the instrument handle (e.g., arms 172), toassist in managing the sutures 28,29 during insertion and tensioning.

The stitching process may be accomplished by any known means, and anyknown suture stitch may be employed. A stitch is desirably secured sothat the suture is not inadvertently separated from the tendon aftercompletion of the repair procedure, necessitating re-entry to thesurgical site. In preferred approaches, the suture is attached to thesoft tissue using a “mattress stitch,” which is well known in the art asbeing a particularly secure stitch which is unlikely to failpostoperatively.

Anchor 132 may then be brought into contact against the underlying bone100. The bone tissue 100 may be that of a shoulder, which comprises ahumeral head, including an outer cortical bone layer 167, which is hard,and inner cancellous bone 169, which is relatively soft. As is typicallythe case for rotator cuff injuries, in this instance the supraspinatustendon 150 has become separated from the humeral head. It is desirableto reattach the tendon 150 to the humeral head. Alternative rotator cuffrepair procedures are also discussed in U.S. Pat. No. 6,524,317, andentitled “Method and Apparatus for Attaching Connective Tissues to BoneUsing a Knotless Suture Anchoring Device”, which is hereby incorporatedby reference in its entirety.

Now with reference to FIG. 7, the proximal end of the instrument 128 orhandle 130 may be tapped, e.g., by using a mallet, to drive the sutureanchor 132 into the bone at a depth of, for example, approximately 6 mm.If viewed through an arthroscope, primary anchor 132 may be driven intothe underlying bone 100 until an anchor depth indicator 112 (e.g., acolored marking or gradation) is visible just above or at the bone 100.Depth indicator 112 is a visual indicator to the user that theappropriate depth for anchor insertion has been reached. This mayindicate that the anchor wings 164 have been inserted at the correctdepth. Insertion to the cortical layer 167 is important to ensureanchoring structure 164′ gains good purchase on the bone.

Next, tension is applied to the free legs 28 until the tendon 150 hasbeen drawn toward the anchor as shown in FIG. 8, and is positioned foran anatomically proper repair and otherwise snugly situated with respectthereto. Non-limiting examples of threshold distances between the tissue150 and the proximal end of the anchor range from 2-8 mm and morepreferably 3-6 mm. The suture may be drawn by hand, by instrument, or acombination thereof.

With suture anchor 132 at a suitable depth, and the tissue in a desiredposition, the anchor wings 164 may be deployed within the bone 100, tolock the position of anchor 132 and to prevent anchor 132 from beingpulled out of the bone 100. A die or driver member (not shown) of theinstrument may push sleeve 174 distally and into the cavity of theanchoring structure, deflecting the wings 164″ radially outward and intothe bone.

Such action may be carried out in a number of ways. For example, a knob168 shown in FIG. 6 may be linked to a driver or die member which, whenturned, allows driver member to be advanced relative to the shaft.Advancing the driver member advances sleeve. The driver member may beadvanced, for example, by pushing on it. Alternatively, a knob may belinked to a driver surface which is ratcheted distally, incrementallymoving sleeve 174. Handles having various actuation mechanisms fordeploying anchors are described in, e.g., U.S. Patent Publication Nos.2008/0051836; 2009/0069823; and 2010/0191283, each of which is herebyincorporated by reference in its entirety.

Anchor 132 may then be released from instrument 128, which may beachieved by a variety of mechanical means as described above. Forexample, the components may be operable to have a weakness or failurepoint that fractures or disconnects upon application of a force ortorque. Some methods for this release are described in U.S. Pat. No.6,585,730, which is hereby incorporated by reference in its entirety.Additionally, the anchor may be implanted in other manners, and withouta sophisticated instrument as described above.

FIG. 9 shows a deployed anchor 100 situated within the bone 100 afterrelease from the anchoring system. A first section of the suture 182 issecured within the anchor while a second section 184 is wedged betweenthe cavity wall and an exterior of the anchor wings 164″. In thisvariation, the suture loops from a first side of the anchor to a secondside via a suture opening located in a tip portion of the locking plug.The suture is locked in several places: a) the suture is compressedbetween the anchor body shaft and the sleeve member; (b) the suture iscompressed between the perpendicular stop surface of the body and thedistal edge of the sleeve; and (c) the suture is compressed between thebone wall and the outer surface of the wing members. This so-calledtri-lock provides safeguards against failure.

Alternative Embodiments

FIGS. 10A-10D show an alternative embodiment of a suture anchorcomponent and in particular, an alternative embodiment of a locking plug210. The locking plug 210 shown in FIGS. 10A-10D is similar to thatshown above except that tip 212 includes ridges 214. The dimensions ofthe ridges are characterized by a ridge height h_(r) ranging from 0.005to 0.015 inch and a ridge length l_(r) ranging from 0.030 to 0.050 inch.The ridges 214 aid in gripping bone as the locking plug is inserted (orpounded) into bone.

FIGS. 11A-11C show an alternative embodiment of a suture anchor assembly300. The anchor 300 is similar to the anchors described above exceptthat sleeve 302 includes a ridged section 304. With reference to FIG.11B, the sleeve 302 is pushed distally by a driver member 306 alonganchor plug member 316. In particular, driver 306 includes a pushsurface 322 which contacts proximal end of sleeve 302 to urge sleevedistally. FIG. 11C shows the ridged section of sleeve registered in thewindow 308 between the wings 312 and 314. The ridges 304 of sleevesupplement the bone locking to secure the anchor in the bone.

Methods for Securing Tissue

FIG. 12 is a flowchart showing the steps of a medical procedure forsecuring connective tissue to bone. This procedure includes the steps ofsecuring a bound limb of a length of one or more sutures to a portion ofconnective tissue (e.g., the rotator cuff tendon) to be attached to aportion of bone (e.g., the humeral head), using any method deemedsuitable to the clinician (Step 410).

Step 420 states to load the length of suture through a suture anchordevice. The suture anchor device may be temporarily attached to aninsertion instrument shaft distal end, having an opening to provide apassage for the length of suture to gain access to the suture anchordevice as described herein. The shaft distal end may also have a driverto deploy an anchoring element, disposed at the proximal end of theanchoring device.

Next, the suture anchor is inserted into a portion of bone, deep enoughso that the anchor device proximal end is in the cancellous bone region.A marker or indicator may be present on the shaft distal end to aid inproper anchor placement. This step may be performed by hammering orpounding in the anchor with a mallet (430).

Step 440 states to apply tension to the free end of the length of sutureso as to draw the bound limb of the length of suture toward the sutureanchor device, thereby drawing the connective tissue closer to theanchor. The free end of the suture is drawn until the portion ofconnective tissue is snugly secured to the portion of bone.

The free suture ends may then be tied to a portion of the handle (orotherwise managed) to maintain tension for the next step.

Step 450 states to deploy the bone locking structure. This is preferablyperformed by pushing on the sleeve component with a driver of theinsertion instrument so as to urge the sleeve into the annular space orcavity formed between the anchor plug component and the bone anchoringstructure. The wings of the bone anchoring structure are deflectedradially outward (flare outward) and into the tissue.

In embodiments, step 450 simultaneously locks the suture and detachesthe inserter from the anchor body. In particular, the sleeve compressesthe suture against the plug member, thereby locking the suture. Thedistal end of the sleeve pushes against stop surface 48 of the anchorbody 16 causing the anchor body to detach along at a predeterminedregion such as engineered notch 55. In embodiments, an engineering notchbetween the anchor body and the end of the insertion instrument shaftbreaks or shears at a predetermined force which is greater than theforce necessary to deploy the sleeve.

Step 460 states to retract the insertion device. This may be carried outmanually or semi automatically. First, the free ends of the suture aredisconnected from the handle. Then, the handle is withdrawn.

In embodiments, the sacrificial region between the anchor plug and theend of the insertion instrument shaft breaks or shears at apredetermined force which is less than the force necessary to pull outthe embedded anchor.

The suture ends may then be trimmed close to the proximal end of theembedded anchor.

FIGS. 13A and 13B show another anchor 510 deployed in a bone. The anchoris shown having an offset or tilt angle (β). The tissue side of thesutures 512 engage the anchor 510 at the distal end section, namely, thedistal tip eyelet 514. Tension, applied to the tissue or bound side ofthe sutures, induces a shift or off-axis force to the anchor (ratherthan pull out the anchor axially). The angle or degree of toggle (Beta)desirably ranges from 0 to 15 degrees and more preferably is between 5and 10 degrees. Tension on the bound suture limb may be applied manuallyby the surgeon, or may result from exercise and use of the tendon postoperation.

Without being bound to theory, the toggle or tilt from the firstposition 520 to the second position 522 is different than most otheranchors having the sutures extend through and down the center of theanchor. When the sutures extend down the center of the anchor, tensionfrom the tissue (or repeated use of the tissue) acts to pull out theanchors. In the present embodiment shown in FIGS. 13A and 13B, tensionor strain on the anchor acts to toggle or tilt the anchor, furtherembedding the anchor in the bone.

Although an exemplary embodiment of the invention has been shown anddescribed, it is to be understood that all the terms used herein aredescriptive rather than limiting, and that many changes, modifications,and substitutions may be made by one having ordinary skill in the artwithout departing from the spirit and scope of the invention. Inparticular, it is noted that the procedures, while oriented toward thearthroscopic repair of the rotator cuff, are applicable to the repair ofany body location wherein it is desired to attach or reattach softtissue to bone, particularly using an arthroscopic procedure.

What is claimed is:
 1. A suture anchor for securing a soft tissue to abone with at least one suture, wherein the suture anchor comprises afirst undeployed configuration in which tissue may be drawn towards thesuture anchor by applying tension to a free limb of the suture, and asecond deployed configuration in which the suture anchor is fixed in thebone and the suture is locked in the suture anchor thereby securing thetissue to the bone, said suture anchor comprising: an anchor body havinga proximal section, an elongate intermediate section, and a distalsection; a bone locking member at least partially disposed about theelongate intermediate section and forming a cavity between an innersurface of the bone locking member and an outer surface of the elongateintermediate section; and a sleeve member which moveably cooperates withthe anchor body and the bone locking member to slide into the cavityalong the elongate intermediate section thereby expanding the bonelocking member and compressing the at least one suture between the outersurface of the elongate intermediate section and an inner surface of thesleeve member.
 2. The suture anchor of claim 1 wherein the bone lockingmember is expandable to a plurality of different sizes.
 3. The sutureanchor of claim 1 wherein the bone locking member comprises a pluralityof deflecting sections which deflect outwardly from the anchor body whenthe sleeve member is urged into said cavity.
 4. The suture anchor ofclaim 3 wherein the plurality of deflecting sections comprises at leastthree discrete wings.
 5. The suture anchor of claim 1 wherein distalsection comprises a bone piercing tip.
 6. The suture anchor of claim 5wherein the bone piercing tip tapers from a proximal base to a distalend, wherein said base has an outer diameter of at least 4 mm.
 7. Thesuture anchor of claim 1 wherein the anchor body is a biocompatiblepolymer.
 8. The suture anchor of claim 1 wherein at least one of thebone locking member and sleeve comprises exterior ridges.
 9. The sutureanchor of claim 8 wherein the distal section of the anchor bodycomprises ridges.
 10. The suture anchor of claim 1 wherein the distalsection of the anchor body comprises a suture guide which guides thesuture from one side of the anchor body to the other side of the anchorbody.
 11. The suture anchor of claim 10 wherein the suture guide is anaperture extending through the distal section of the anchor body. 12.The suture anchor of claim 1 wherein the cavity is an annular space. 13.A knotless suture anchoring system for anchoring a length of suture withrespect to a bone, comprising: an anchor insertion instrument comprisinga handle, and an elongate rigid shaft extending distally from thehandle, said shaft comprising a distal end section; an anchor bodydetachably connected to the distal end section of the elongate rigidshaft, said anchor body comprising a proximal end section, an elongateintermediate section, and a distal end section, the distal end sectioncomprising a suture carrying portion allowing the suture to pass from afirst side of the anchor body to an opposite side of the anchor body; abone locking member disposed on the anchor body, the bone locking membercomprising: a base which cooperates with said distal end section of theanchor body to hold the base to the anchor body; and a bone anchoringstructure extending from the base and radially spaced from theintermediate section of the anchor body such that a cavity is definedbetween an outer surface of the anchor body and the inner surface of thebone anchoring structure, and wherein the cavity is sufficient in sizeto allow the length of suture to be drawn through the cavity and to thesuture carrying portion; and a sleeve member slidably disposed on theshaft distal end section of the instrument and proximal to the anchorbody, the sleeve member having an outer diameter sufficient in size andshape to radially expand the anchoring structure when pushed along theshaft distal end section and into the cavity, and the sleeve memberhaving an inner diameter sufficient in size and shape to compress alength of suture between the anchor body and an inner surface of thesleeve.
 14. The system of claim 13 further comprising a snare extendingthrough at least a portion of the insertion instrument and the suturecarrying portion of the anchor body such that when a distal portion ofthe snare is affixed to the suture, withdrawal of the snare pulls thesuture through the suture carrying portion of the anchor body and thedistal portion of the insertion instrument.
 15. The system of claim 13wherein the distal end section of the anchor comprises a pointed tip.16. The system of claim 13 further including a section of tensileweakness along the instrument shaft permitting the shaft to be detachedfrom the anchor body proximal end upon application of a predeterminedtensile force on the shaft in the proximal direction.
 17. The system ofclaim 13 wherein the bone anchoring structure has a plurality ofdeflectable wings, and each wing comprises a plurality of exteriorridges.
 18. The system of claim 13 wherein the cavity is an annularspace.
 19. A method for knotless securing of soft tissue to bone, themethod comprising: stitching tissue with at least one suture; loading ananchor assembly with the at least one suture, the anchor assembly beingdetachably connected to the end of an insertion instrument; manipulatingthe anchor assembly into the bone; tensioning a free end of the sutureto approximate the tissue to the anchor assembly; moving a sleeve memberinto the anchor assembly to deploy a bone locking structure of theanchor assembly and to compress the suture; and retracting the insertioninstrument leaving the anchor assembly embedded in the bone, and thetissue secured to the bone.
 20. The method of claim 19 wherein loadingthe anchor assembly with the at least one suture comprises loading theanchor assembly with a plurality of sutures.
 21. The method of claim 20wherein loading the anchor assembly is performed by snaring the sutures.22. The method of claim 21 wherein snaring is performed by inserting thelengths of the sutures in a wire loop of a snare device detachablyaffixed to the distal section of the shaft, and pulling on a snare gripto draw the sutures through the anchor assembly and the instrument. 23.The method of claim 19 wherein the manipulating the anchor and sutureinto the bone comprises hammering the proximal end of the insertioninstrument.
 24. The method of claim 19 wherein the tensioning isperformed prior to the manipulating step.
 25. The method of claim 19wherein the tissue is a rotator cuff tendon and the bone is the humeralhead.
 26. The method of claim 19 wherein the moving step comprisescompressing a first section of suture between the anchor body and thesleeve member and a second section of the suture between a bone surfaceand an exterior of the bone locking structure.
 27. The method of claim19 wherein the moving step comprises pushing the sleeve into the cavityuntil a stop on the anchor body prevents further movement.
 28. Themethod of claim 19, wherein said tensioning is performedsemi-automatically.
 29. The method of claim 19 further comprisingtoggling the anchor assembly.
 30. The method of claim 29 wherein thetoggling creates a tilt angle ranging from 5 to 10 degrees.
 31. Themethod of claim 29 wherein the toggling is performed by applying tensionon the tissue side of the suture.